Radiology Billing Guide: CPT & Modifiers
Radiology is one of the few specialties where a single study can be split into two separately payable claims — one for the radiologist's reading, one for the machine that produced the images. Get that split wrong and the claim denies as a duplicate, even though the coding was otherwise perfect.
This is a coding reference, not a sales page. It covers the professional/technical component split, the modifiers radiology actually uses, the CPT ranges a radiology coder works in every day, and why interventional radiology codes no longer behave like the rest of the chapter.
Quick Answers
- Modifier 26 bills the professional component — the radiologist's supervision and interpretation, and the signed report.
- Modifier TC bills the technical component — equipment, supplies, film/PACS, and the technologist.
- No modifier = global. One entity owns both halves, so it bills the whole code once.
- The PC/TC indicator on the Medicare Physician Fee Schedule decides whether a split is even allowed for a given CPT code. Not every radiology code can be split.
- Interventional radiology mostly doesn't split this way. Modern IR codes bundle catheter placement, imaging supervision and interpretation, and the intervention into one code.
Professional vs. Technical Component (PC/TC)
Most diagnostic imaging codes describe two distinct pieces of work performed by two different parties. CPT gives you one code for the study, and the modifier tells the payer which piece you are billing.
| What you bill | Modifier | What it covers | Who typically bills it |
|---|---|---|---|
| Professional component | 26 | Supervision, interpretation, and the signed written report | Hospital-based radiologist or a reading group |
| Technical component | TC | Equipment, supplies, contrast, technologist time, image storage | Hospital, IDTF, or the practice that owns the equipment |
| Global service | (none) | Both halves together | Freestanding imaging center that owns the equipment and employs the reader |
The modifier is not a preference — it is a statement of fact about who owns what. If the hospital owns the scanner and your radiologist reads the study, the hospital bills TC and you bill 26. Billing globally in that situation duplicates the hospital's claim and both sides get scrutinized.
Read the PC/TC indicator before you split anything
Every code on the Medicare Physician Fee Schedule carries a PC/TC indicator that controls what is legal to bill:
| Indicator | Meaning for radiology |
|---|---|
| 0 | Physician service only — no professional/technical split exists. Do not append 26 or TC. |
| 1 | The code has both components. 26 and TC are both valid, and so is the global. |
| 2 | Professional component only. The code already is the 26 side; appending 26 is redundant. |
| 3 | Technical component only. The code already is the TC side. |
| 4 | Global test only — the components are reported with separate distinct codes, not modifiers. |
| 9 | The concept does not apply to this code. |
A large share of "invalid modifier" rejections in imaging come from appending 26 to an indicator-0 or indicator-3 code out of habit.
Place of service changes the answer
The same CPT code is billed three different ways depending on where the study happened and who owns the equipment:
- Inpatient or hospital outpatient (POS 21, 22): the facility bills the technical side on its own claim; the radiologist bills the code with modifier 26.
- Freestanding imaging center that employs the reader: global — no modifier.
- IDTF or mobile unit performing the scan, outside radiologist reading it: IDTF bills TC, reader bills 26.
- Physician office (POS 11) with in-office equipment: global, but watch the anti-markup rules when the interpretation is purchased from an outside physician.
Radiology Modifier Reference
Radiology uses a small, stable set of modifiers. These are the ones that appear on diagnostic imaging claims most often, and what each one is actually asserting.
| Modifier | Use it when | Common mistake |
|---|---|---|
| 26 | Billing only the interpretation and report | Appended to a code with no professional component |
| TC | Billing only the equipment/technical side | Billed alongside a global claim for the same study |
| 50 | The same procedure was performed bilaterally in one session | Used on a code whose descriptor is already bilateral |
| LT / RT | Identifying the side when the payer wants sides on separate lines | Appended in addition to 50 when the payer wants one or the other |
| 52 | The service was reduced — fewer views than the descriptor requires | Used for a study the patient could not tolerate after it started (that is 53) |
| 53 | The procedure was started and then discontinued for the patient's wellbeing | Used for a cancellation before the patient was prepped |
| 59 / XE, XP, XS, XU | Unbundling a code pair when the edit allows it and documentation supports it | Applied reflexively to clear an NCCI edit without a separate site, session, or encounter |
| 76 | The same physician repeated the same study on the same day | Omitted, so the second study denies as an exact duplicate |
| 77 | A different physician repeated the same study on the same day | Swapped with 76 |
| 22 | Substantially greater work than the code contemplates | Submitted without the report language and time that justify it |
Modifier 59 and the X{EPSU} set deserve particular discipline. They override a National Correct Coding Initiative edit, which means they are an assertion that the two services were genuinely separate — different encounter, different site, different session. The documentation has to say so before the modifier goes on the claim.
Radiology CPT Code Ranges
The radiology chapter is organized by modality, and knowing the ranges makes it much faster to spot a code that landed in the wrong family.
| Range | Contents |
|---|---|
| 70010–76499 | Diagnostic radiology (plain film, CT, MRI, angiography) organized head-to-toe |
| 76506–76999 | Diagnostic ultrasound, including obstetric and vascular studies |
| 77001–77022 | Radiologic guidance — fluoroscopic, CT, MR, and ultrasound guidance for procedures |
| 77046–77067 | Breast imaging: MRI, mammography, tomosynthesis, and screening |
| 77071–77086 | Bone and joint studies, including bone density (DXA) |
| 77261–77799 | Radiation oncology — planning, simulation, delivery, and management |
| 78012–79999 | Nuclear medicine, diagnostic and therapeutic |
Two habits prevent most range-level errors. First, code the study that was actually performed, not the study that was ordered — if the order said "CT abdomen" and the radiologist read abdomen and pelvis, the report governs. Second, contrast status is part of the code, not a modifier: "without contrast," "with contrast," and "without followed by with" are three different CPT codes in most families.
Views, laterality, and contrast are code selectors
Many radiology descriptors are defined by a minimum number of views. A "complete" study that documents fewer views than the descriptor requires is either the lesser code or the same code with modifier 52 — never the complete code billed as-is. The same applies to laterality: if the descriptor is unilateral and both sides were imaged, that is modifier 50 or two lines with LT and RT, depending on the payer's preference.
Interventional Radiology Bundling
Interventional radiology is where the PC/TC habits of diagnostic imaging stop working. Over several code-set revisions, CPT collapsed the old component-coding model — where you reported the catheter placement, the imaging supervision and interpretation, and the intervention as separate codes — into single comprehensive codes.
The classic example is lower-extremity angioplasty. The old pattern paired a surgical code with a separate radiological supervision-and-interpretation code. Those pairs were deleted and replaced by codes that include the catheter placement, the imaging, and the intervention in one descriptor. Reporting the deleted-era components alongside the new code is a bundling denial, not a coding preference.
What the modern IR codes already include
When a comprehensive IR code is in play, treat the following as included unless the CPT guidelines for that family say otherwise:
- Access to the vessel and the catheter placement necessary to reach the treatment site
- Imaging supervision and interpretation performed to guide the intervention
- Roadmap and completion angiography of the treated territory
- Closure of the access site
Diagnostic angiography performed in the same session is the frequent gray area. It is separately reportable only when it is a genuinely new diagnostic study — no prior study exists, or the prior study is inadequate, or the patient's condition changed — and the report has to document that reasoning explicitly. "We looked first, then treated" is not, by itself, a separate diagnostic study.
Territory and vessel-family rules
Vascular IR families are built around territories and vessel orders rather than a flat one-code-per-thing structure. Two rules carry most of the weight:
- Report the highest order of selectivity reached in a vascular family, once. Lower-order catheterizations along the way are included, not separately reportable.
- Each additional vascular family accessed through a separate selective path gets its own code. Which is why the dictated report has to name the vessels, in order.
Add-on codes in these families carry their own rules about how many times they can be reported per session and which primary codes they attach to. Check the parenthetical instructions under the primary code before adding a second unit.
NCCI edits are the IR coder's daily tool
The National Correct Coding Initiative publishes procedure-to-procedure edit pairs quarterly, along with a modifier indicator for each pair. An indicator of 0 means no modifier will ever unbundle that pair. An indicator of 1 means an appropriate modifier may unbundle it when the documentation supports a separate site, session, or encounter. Checking the indicator before appending a modifier is the difference between a clean unbundle and a post-payment audit finding.
Documentation That Supports the Code
Radiology denials are usually decided by the report, not the claim form. A report that supports the code it was billed with contains:
- A complete order from the referring provider, with the clinical indication that establishes medical necessity
- The specific study performed — modality, body part, number of views, and contrast status in the language the CPT descriptor uses
- Laterality, stated explicitly, when the code is unilateral
- An ICD-10 diagnosis that matches the indication, coded to the highest level of specificity the documentation supports
- Evidence of supervision at the level the code requires, when contrast or guidance is involved
- A signed, dated interpretation — the professional component does not exist without the written report
For repeat studies on the same date, the report should also state why the study was repeated. That sentence is what supports modifier 76 or 77 when the payer asks.
Where Radiology Claims Fail at the Code Level
These are coding-level failures — the kind you fix by changing what is on the claim, not by appealing:
- Global billing when the facility already billed the technical component
- Modifier 26 on a code whose PC/TC indicator does not allow a split
- A second study on the same date with no 76 or 77, denying as an exact duplicate
- Bilateral studies billed as two units instead of modifier 50, or vice versa, depending on the payer
- Component-era IR codes reported alongside the comprehensive code that replaced them
- Contrast status on the claim that does not match the contrast status in the report
- An ICD-10 code that does not support medical necessity for the modality billed
Denial patterns that are not coding problems — prior authorization workflows, payer policy disputes, appeals strategy, and A/R follow-up on interventional radiology claims — are a different discipline. Those are covered on our radiology billing services page.
Frequently Asked Questions
What is the difference between modifier 26 and modifier TC?
Modifier 26 bills the professional component — the radiologist's supervision, interpretation, and signed report. Modifier TC bills the technical component — the equipment, supplies, contrast, and technologist time. If one entity owns both, the code is billed globally with no modifier at all.
When should a radiology study be billed globally?
Bill globally when the same entity owns the equipment and employs or contracts the interpreting physician — typically a freestanding imaging center or a physician office with in-office equipment. If a hospital or IDTF performed the scan, that facility bills the technical component and the reading physician bills the code with modifier 26.
What is the PC/TC indicator and where do I find it?
The PC/TC indicator is a field on the Medicare Physician Fee Schedule relative value file that tells you whether a code can be split into professional and technical components. Indicator 1 means both components exist and 26 and TC are valid; indicator 0, 2, 3, 4, and 9 each mean the split is either unavailable or already built into the code.
Why do interventional radiology codes deny as bundled?
Modern interventional radiology codes are comprehensive: they already include the vascular access, the catheter placement needed to reach the treatment site, the imaging supervision and interpretation, and the completion angiography. Reporting those pieces separately alongside the comprehensive code triggers a bundling edit. Diagnostic angiography is separately reportable only when it is a genuinely new diagnostic study and the report documents why.
Do I use modifier 76 or 77 for a repeat study?
Use modifier 76 when the same physician repeats the same procedure on the same date, and modifier 77 when a different physician repeats it. Without one of them, the second line denies as an exact duplicate. The report should state why the study was repeated.
Is modifier 50 or LT/RT correct for bilateral imaging?
It depends on the payer and on the code. If the descriptor is unilateral and the payer accepts modifier 50, report one line with 50. Some payers instead want two lines with LT and RT. If the descriptor is already bilateral, neither modifier belongs on the claim.